As is known to all, LED illumination has irreplaceable advantages. It is energy saving, has very low power consumption, has a nearly 100% electro-optical power conversion, can save more than 80% of energy with the same illumination efficiency compared with the traditional light source, and has a long lifespan. In view of the above advantages, people more and more frequently use LEDs as light sources, for example, numerous LED retrofit lamps in the market. Such LED retrofit lamps have a profile of a traditional light source such as an incandescent lamp or lamp tube, such that they, as light sources, can be adapted to the existing illumination systems.
The related art discloses an LED retrofit lamp which includes: a driver housing for accommodating a driver; a heat sink fixed on the driver housing through an end of thereof, wherein the other end of the heat sink is in thermal conduct with a printed circuit board carrying an LED chip. In addition, in order to achieve the predetermined optical effects, the LED retrofit lamp usually further includes an additional optical component, such as a lens. The lens needs to be fixed on an inner wall of a light emergent opening defined by the heat sink. In the prior art, in order to fix the driver housing and the lens on the heat sink, the method of fastening bolt, glue, or snap-fit connection is usually employed. However, fixing the lens on the heat sink by a fastening bolt will inevitably affect the optical effects of the lens. This is because the lens must be drilled for the fastening bolt to go through. When the glue is used for connection, in the case where an electronic device in the LED retrofit lamp is out of work and needs to be changed, the glue cannot be removed to disassemble the leans or the driver housing. When the snap-fit connection is employed, as a hook which may be provided is within the heat sink and is out of reach, the methods using violence can only be used when it is necessary to disassemble the LED retrofit lamp, which will inevitably damage the driver housing or the lens.